R-matrix predictions on 4f 2 levels and 4fnf Rydberg series of barium with J=4-6

Calculational results for the photoionization cross sections leading to the ionic Mg + (3s, 3p, 4s and 3d) states from the excited 3s3p 1,3 P o states of atomic magnesium are reported in the energy region from the first ionization threshold up to the Mg + (4p) threshold limit. For these calculations, we have used an enhanced non-iterative variational R-matrix approach combined with multichannel quantum-defect theory at the R-matrix surface. Autoionizing doubly excited 1,3 S, 1,3 P and 1,3 D resonance structures converging to the Mg + (3p, 4s, 3d and 4p) thresholds are discussed with resonant energies E r , effective quantum numbers n * and widths . The present photoionization cross sections are in good agreement with previous available calculations. There is excellent agreement between length and velocity gauges in our calculations.

Section: Discussionmentioning

confidence: 54%

“…We have also used the same ideas of eigenphase sum gradients as described in [24,25,29] for the calculations of the resonance parameters, such as the resonance positions E r , effective quantum numbers n * and widths . The diagonalization of K oo phys gives eigenvalues λ k .…”

Section: Calculational Descriptionmentioning

confidence: 99%

Photoionization of the excited 3s3p^1,3P^ostates of atomic magnesium

Kim¹

2001

“…Thus, in the energy region between the C 3+ 2p and 3s thresholds, the resonances belonging to the various series converging to the 3s, 3p and 3d thresholds perturb each other so that none of the series exhibit regularity, as is evident from tables 3-5. However, the details of the autoionizing resonances are obtained using the eigenphase sum technique [16], despite the complexity of the cross sections owing to the perturbations among series.…”

Section: Photoionization Between 2s and 3s Thresholds Of C 3+ From Th...mentioning

confidence: 99%

Photoionization of the ground state of the Be-like C²⁺ ion leading to C³⁺ 2l and 3l states

Kim

Manson

2004

Total and partial photoionization cross sections of the Be-like C 2+ ion leading to the C 3+ 2l and 3l (l = 0, 1) states from the 1 S ground state have been calculated. The lower members of all autoionizing Rydberg series converging to the C 3+ 2p, 3s, 3p, and 3d thresholds are identified and their energies and widths are determined. Except for the resonances converging to the C 3+ 2p threshold, all of the resonance series are perturbed by overlapping series converging to other thresholds. In addition, the 4s4p 1 P resonance is found to lie just below the C 3+ 3d threshold. The calculations show excellent agreement between length and velocity gauges. Comparison with experiment for the photoionization of a mixture of the 1 S ground state and 3 P metastable states of C 2+ in the photon energy range 40.8-56.9 eV shows good agreement with the present theoretical results; for the comparison, a calculation of photoionization of the metastable state was also performed. The present calculations are also compared with other previous theoretical and experimental results.

“…In the autoionizing energy range, the number of physical solutions is equal to N o , the number of open channels. Identification and quantitative information of the positions and widths of autoionizing resonances can be obtained independently of the excitation scheme, by analysing the energy dependence of the density of states, defined by the mixing coefficients of the closed channels in the N o physical wavefunctions ρ (E) (Luc-Koenig et al 1994). The strengths of the channel couplings are studied through the phase-shifted MQDT parameters (Giusti-Suzor and Fano 1984, Lecomte 1987) derived from the K LS matrix.…”

Section: Mqdt Treatmentmentioning

confidence: 99%

EigenchannelR-matrix study of two-photon excitation of low-lying autoionizing states in strontium: dielectronic core-polarization effects

Luc‐Koenig

Aymar

Lecomte

et al. 1998

Self Cite

Two-photon ionization processes from the ground state of strontium are studied employing the jj -coupled eigenchannel R-matrix approach combined with the multichannel quantum-defect theory (MQDT). The calculations satisfactorily reproduce the experimental spectra corresponding to two-photon excitation of the 4d6d J = 0 e , J = 2 e and 5p 2 1 S 0 , 1 D 2 low-lying autoionizing resonances, confirming that the method is suitable to account for the spin-orbit interaction effects in the multiphoton excitation of heavy atoms. It is also shown that the dielectronic core polarization cannot be disregarded in the description of these highly correlated resonances, as it affects significantly both their energy positions and autoionization widths.